High-strength KOBM steel slag binder activated by carbonation

The feasibility of developing a high strength KOBM (Klockner Oxygen Blown Maxhutte) steel slag binder activated by carbonation as an alternative cementing material was investigated. After two-hour carbonation reaction, steel slag compacts displayed a 2 h compressive strength of 80 MPa with a CO2 uptake of 13%. Early strength gain was attributed to the carbonation of the slag's γ-C2S component. Subsequent hydration enhanced the ultimate strength to 109 MPa, owing to the latent hydraulic reactivity of the β-C2S component. The carbon-activated slag presented a more sustainable alternative to Portland cement as a primary binder for building products. In addition to conserving the natural resources and recycling the wastes, a potential carbon sink for the steel industry can be realized through its use.